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Abstract:

A robot arm (50) of the present invention includes, as a direct acting
extensible/retractable joint (J3), an arm section (2) constituted by an
upper structure group (20) and a lower structure group (21). Groups (20)
and (21), having an arrangement in which structures are connected in
series, partially engage so as to form a direct rigid combined structure,
and are separated so as to release the rigid structure. An arm length can
be adjusted arbitrarily. Section (2) can have a plane surface having no
gap to prevent entry of a finger/dust. Separation of Groups (20) and (21)
allows an upper structure (22) and a lower structure (23) to rotate
around their rotational axes, to realize compact storage inside a robot
arm supporting member (1). It is thus possible to prevent significantly
entry of a finger/dust, and provide a compact direct acting extensible
and retractable arm mechanism.

Claims:

1. A direct acting extensible and retractable arm mechanism comprising: a
robot arm supporting member; and an arm section being extensible and
retractable directly from one of ends of the robot arm supporting member,
the arm section being such that a hand section is attachable to one of
ends of the arm section, the arm section being constituted by (i) a first
structure group in which a plurality of first structures are coupled with
each other in series in such a manner that adjacent ones of the plurality
of first structures are coupled with each other via a corresponding one
of a plurality of first coupling axes in a direction which is orthogonal
to a direction of the corresponding one of the plurality of first
coupling axes and (ii) a second structure group in which a plurality of
second structures are coupled with each other in series in such a manner
that adjacent ones of the plurality of second structures are coupled with
each other via a corresponding one of a plurality of second coupling axes
in a direction which is orthogonal to a direction of the corresponding
one of the plurality of second coupling axes, the plurality of first
structures being identical with each other in width in a direction
parallel to the plurality of first coupling axes, the plurality of second
structures being identical with each other in width in a direction
parallel to the plurality of second coupling axes, the first structure
group and the second structure group being coupled with each other in
such a manner that one of two end first structures of the plurality of
first structures, on a hand section side, and one of two end second
structures of the plurality of second structures, on the hand section
side, are coupled with each other, the robot arm supporting member
including drive means for (i) pressing the first structure group and the
second structure group so that the first structure group and the second
structure group become closer to each other and become in contact with
each other, (ii) causing the first structure group and the second
structure group to overlap each other so that a surface of the first
structure group and a surface of the second structure group, which
surfaces are in contact with each other, do not slip with respect to each
other, and (iii) driving the first structure group and the second
structure group in a direction in which the arm section is extensible, in
a case where the drive means causes the first structure group and the
second structure group to overlap each other, the first structure group
and the second structure group forming such a rigid arm section that
rotation of each of the plurality of first structures via the
corresponding one of the plurality of first coupling axes and rotation of
each of the plurality of second structures via the corresponding one of
the plurality of second coupling axes are prevented, at least one of the
first structure group and the second structure group is such that
adjacent ones of structures engage with each other via their side
surfaces, and form a plane surface having no gap, which plane surface
faces and is in contact with a surface of the other one of the first
structure group and the second structure group, the robot arm supporting
member including separation means in the robot arm supporting member, in
a case where the drive means carries out reverse driving, the separation
means causes the first structure group and the second structure group to
be separated from each other so that (i) each of the plurality of first
structures is rotatable around the corresponding one of the plurality of
first coupling axes and (ii) each of the plurality of second structures
is rotatable around the corresponding one of the plurality of second
coupling axes.

2. The direct acting extensible and retractable arm mechanism as set
forth in claim 1, wherein: in a case where (i) the drive means causes the
first structure group and the second structure group to overlap each
other and therefore (ii) the arm section becomes rigid in such a manner
that the rotation of each of the plurality of first structures via the
corresponding one of the plurality of first coupling axes and the
rotation of each of the plurality of second structures via the
corresponding one of the plurality of second coupling axes are prevented,
one of the first structure group and the second structure group is
provided above the other one of the first structure group and the second
structure group; and the one of the first structure group and the second
structure group is such that adjacent ones of structures engage with each
other via their side surfaces and forms a plane surface having no gap,
which plane surface is opposite to a surface that is in contact with a
surface of the other one of the first structure group and the second
structure group.

3. The direct acting extensible and retractable arm mechanism as set
forth in claim 1, wherein: the first structure group is such that
adjacent ones of the plurality of first structures engage with each other
via their side surfaces and form a plane surface having no gap, which
plane surface is opposite to a surface that is in contact with a surface
of the second structure group; and the second structure group is such
that adjacent ones of the plurality of second structures engage with each
other via their side surfaces and form a plane surface having no gap,
which plane surface is opposite to the surface that is in contact with
the surface of the first structure group.

4. The direct acting extensible and retractable arm mechanism as set
forth in claim 1, wherein: the one of two end first structures of the
plurality of first structures and the one of two end second structures of
the plurality of second structures are physically attached to each other
or physically welded with respect to each other.

5. The direct acting extensible and retractable arm mechanism as set
forth in claim 1, wherein: the one of two end first structures of the
plurality of first structures and the one of two end second structures of
the plurality of second structures are combined with a common block.

6. The direct acting extensible and retractable arm mechanism as set
forth in claim 1, further comprising: a pressing member for supporting
said pressing of the first structure group and the second structure
group, the pressing member pressing at least one of the first structure
group and the second structure group.

7. The direct acting extensible and retractable arm mechanism as set
forth in claim 1, wherein: the drive means is such that (i) the drive
means includes a drive mechanism constituted by a gear(s) and an actuator
for rotating the gear(s), and the gear(s) is in contact with one of the
first structure group and the second structure group so as to drive both
the first structure group and the second structure group, or (ii) the
drive means includes two drive mechanisms each being constituted by a
gear(s) and an actuator for rotating the gear(s), and the gear(s) of one
of the two drive mechanisms is in contact with one of the first structure
group and the second structure group and the gear(s) of the other one of
the two drive mechanisms is in contact with the other one of the first
structure group and the second structure group, so as to drive both the
first structure group and the second structure group.

8. The direct acting extensible and retractable arm mechanism as set
forth in claim 7, wherein: the gear is provided between the first
structure group and the second structure group.

9. The direct acting extensible and retractable arm mechanism as set
forth in claim 1, wherein: a length from a surface of each of the
plurality of first structures constituting the first structure group,
which surface is in contact with the second structure group, to an
opposite surface of each of the plurality of first structure, and a
length from a surface of each of the plurality of second structures
constituting the second structure group, which surface is in contact with
the first structure group, to an opposite surface of each of the
plurality of second structures, are identical with each other or
different from each other.

10. The direct acting extensible and retractable arm mechanism as set
forth in claim 1, wherein: in a case where (i) the drive means causes the
first structure group and the second structure group to overlap each
other and therefore (ii) the arm section becomes rigid in such a manner
that the rotation of each of the plurality of first structures via the
corresponding one of the plurality of first coupling axes and the
rotation of each of the plurality of second structures via the
corresponding one of the plurality of second coupling axes are prevented,
one of the first structure group and the second structure group is
provided above the other one of the first structure group and the second
structure group; and a plurality of coupling axes of the other one of the
first structure group and the second structure group are located below a
plurality of coupling axes of the one of the first structure group and
the second structure group in a direction of gravitational force.

11. The direct acting extensible and retractable arm mechanism as set
forth in claim 1, wherein: in a case where (i) the drive means causes the
first structure group and the second structure group to overlap each
other and therefore (ii) the arm section becomes rigid in such a manner
that the rotation of each of the plurality of first structures via the
corresponding one of the plurality of first coupling axes and the
rotation of each of the plurality of second structures via the
corresponding one of the plurality of second coupling axes are prevented,
one of the first structure group and the second structure group is
provided above the other one of the first structure group and the second
structure group; and each of a plurality of coupling axes of the other
one of the first structure group and the second structure group is
located below a region between adjacent ones of a plurality of coupling
axes of the one of the first structure group and the second structure
group in a direction of gravitational force.

12. The direct acting extensible and retractable arm mechanism as set
forth in claim 1, wherein: a surface of the first structure group and a
surface of the second structure group, which surfaces are in contact with
each other, have, respectively, gear sections which engage with each
other.

13. The direct acting extensible and retractable arm mechanism as set
forth in claim 12, wherein: each of a plurality of structures
constituting one of the first structure group and the second structure
group has a plurality of gear sections on its surface which is in contact
with a surface of the other one of the first structure group and the
second structure group; and the plurality of gear sections engage with
both gear sections of adjacent ones of a plurality of structures of the
other one of the first structure group and the second structure group.

14. The direct acting extensible and retractable arm mechanism as set
forth in claim 1, wherein: the robot arm supporting member is capable of
storing, inside the robot arm supporting member, the first structure
group and the second structure group which have been separated from each
other by the separation means; and the first structure group and the
second structure group, separated from each other by the separation
means, are stored along an inner shape of the robot arm supporting member
by (i) the rotation of each of the plurality of first structures via the
corresponding one of the plurality of first coupling axes and (ii) the
rotation of each of the plurality of second structures via the
corresponding one of the plurality of second coupling axes.

16. The robot arm as set forth in claim 15, wherein: one of ends of the
arm section of the direct acting extensible and retractable arm mechanism
is provided with an end effector.

Description:

TECHNICAL FIELD

[0001] The present invention relates to a mechanism of a robot arm.
Specifically, the present invention relates to (i) a direct acting
extensible and retractable arm mechanism which realizes high safety, a
compact body, and prevention of entry of dust and the like, and (ii) a
robot arm including the direct acting extensible and retractable arm
mechanism.

BACKGROUND ART

[0002] In recent years, there has been a reduction in population of
workers in an aging society with a falling birthrate. Because of such a
reduction in population of workers, there has been demand for a robot arm
which (i) can manufacture a product in cooperation with a human at a
production site or (ii) can support a daily life of an old person or a
daily life of a handicapped person.

[0003] A robot arm constituted by rotational joints has an arrangement in
which a plurality of rotational joints 103 and a plurality of arm
sections 102 are, alternately, connected to each other in series between
a base 100 and an end effector 101 (see (a) and (b) of FIG. 19). With the
arrangement, in a case where a position and orientation of the end
effector 101 are determined, rotational angles of the plurality of
rotational joints 103 are generally determined uniquely. That is, there
is a problem that it is not possible to determine arbitrarily the
position of the end effector 101 and a position of each of the rotational
joints 103. For this reason, in a case where the end effector 101 is
moved from a position illustrated in (a) of FIG. 19 to a position
illustrated in (b) of FIG. 19, for example, the plurality of arm sections
102 become close to each other. In this case, there is an increase in
risk that an object located in the vicinity of the plurality of arm
sections 102 might be sandwiched between the plurality of arm sections
102. Further, since one of the plurality of rotational joints 103 is
moved upward in FIG. 19 from a straight line (shown in a dashed line)
connecting the base 100 and the end effector 101 to each other, there is
an increase in risk that the one of the plurality of rotational joints
103 becomes in contact with, or crashes against an object located in the
vicinity of the robot arm. Such an arrangement is not suitably applicable
to a robot arm which operates in the vicinity of a person in a daily life
or the like.

[0004] In order to reduce such risks, there has been proposed a robot arm
having a direct acting extensible and retractable arm mechanism which
employs a direct acting joint in place of a rotational joint. The direct
acting extensible and retractable arm mechanism employs linear extensible
and retractable motion, and has been applied to a crane vehicle, a ladder
truck, etc. In order to ensure a high rigidity, the linear extensible and
retractable arm mechanism, applied to the crane vehicle, the ladder
truck, etc., is such that a mechanism of an arm section becomes larger
with increasing distance from a hand section toward a root section
serving as a base section. Accordingly, it is necessary for the direct
acting extensible and retractable arm mechanism, applied to the crane
vehicle, the ladder truck, etc., to have the base section and the arm
section, both of which are large and heavy.

[0005] Further, Patent Literatures 1 through 3 also describe a robot arm
having a linear extensible and retractable arm mechanism. However, such a
robot arm has danger in a case where the robot arm operates in the
vicinity of a human in a daily life or the like. Further, a general
direct acting mechanism used in an industrial machine keeps its linear
mechanism all the time. For this reason, in a case where the direct
acting mechanism is stored, the direct acting mechanism thus stored
protrudes from a main body of the robot arm. That is, there remains
danger for a human in a case where the direct acting mechanism operates
in the vicinity of the human in a daily life or the like.

[0006] Patent Literature 4 describes an arm employing a direct extensible
and retractable arm mechanism, which arm has a low risk that the arm
might be in contact with or crush against an object located in the
vicinity of the arm. However, this arm ensures its rigidity only in a
direction of gravitational forth. That is, the arm is not suitably used
as a robot arm that is used in a daily life or the like, in which (i)
realization of an arbitrary position of the arm and an arbitrary posture
of the arm are required, and (ii) various operations are required, such
as holding an object with an end effector, pressing a button, and
exhibiting force not only in the direction of gravitational force but
also in directions of 6 axes of a position and a posture. Furthermore,
since an overload concentrates on an axis, it is difficult to ensure a
high rigidity of the arm. Moreover, since a lot of gaps are formed on an
upper surface between links, it is likely that (i) a finger is sandwiched
inside the direct acting extensible and retractable arm mechanism and
(ii) dust enters inside the direct acting extensible and retractable arm
mechanism. That is, this arm cannot be suitably used as a robot ram used
in the vicinity of a human in various environments, e.g., when being used
in a daily life.

[0015] As to a robot arm which (i) operates in the vicinity of a human to
(i) produce a product in cooperation with the human at a production site
or (ii) operates in the vicinity of an aged person or a handicapped
person to support a daily life of the aged person or a daily life of the
handicapped person, use of a direct acting extensible and retractable arm
mechanism in place of a rotational joint leads to an improvement in
safety. However, with such a direct acting extensible and retractable arm
mechanism, there are such problems that (i) it is difficult to ensure a
high rigidity for each of positions and postures of the direct acting
extensible and retractable arm mechanism, (ii) it is difficult to prevent
a finger from being sandwiched inside the direct acting extensible and
retractable arm mechanism or dust from entering the direct acting
extensible and retractable arm mechanism, and (iii) the direct acting
extensible and retractable arm mechanism has a large size when being
stored.

[0016] The present invention is made in view of the problems. An object of
the present invention is to provide a direct acting extensible and
retractable arm mechanism of a robot arm which can be used safely in the
vicinity of a human in a daily life or the like.

Solution to Problem

[0017] The inventors of the present invention has completed the present
invention by finding such a direct acting extensible and retractable arm
mechanism that (i) two structure groups constitute a single arm section,
(ii) the arm section has a flexible extensibility and a flexible
retractility, (iii) the arm section has a high rigidity and a high
strength in such a manner that the arm section becomes rigid in a case
where the two structure groups overlap each other to form the arm section
in cooperation with each other, (iv) particularly, the arm section can
cause a surface, via which entry of a finger or dust is likely to occur,
to be a plane surface having no gap, and (v) the direct acting extensible
and retractable arm mechanism can be reduced in size when being stored in
such a manner that each of a plurality of structures constituting the one
of the two structure groups and each of a plurality of structures
constituting the other one of the two structure group can be rotate
around a rotational axis in a case where the two structure groups are
separated from each other.

[0018] That is, in order to attain the object, a direct acting extensible
and retractable arm mechanism of the present invention includes: a robot
arm supporting member; a robot arm supporting member; and an arm section
being extensible and retractable directly from one of ends of the robot
arm supporting member, the arm section being such that a hand section is
attachable to one of ends of the arm section, the arm section being
constituted by (i) a first structure group in which a plurality of first
structures are coupled with each other in series in such a manner that
adjacent ones of the plurality of first structures are coupled with each
other via a corresponding one of a plurality of first coupling axes in a
direction which is orthogonal to a direction of the corresponding one of
the plurality of first coupling axes and (ii) a second structure group in
which a plurality of second structures are coupled with each other in
series in such a manner that adjacent ones of the plurality of second
structures are coupled with each other via a corresponding one of a
plurality of second coupling axes in a direction which is orthogonal to a
direction of the corresponding one of the plurality of second coupling
axes, the plurality of first structures being identical with each other
in width in a direction parallel to the plurality of first coupling axes,
the plurality of second structures being identical with each other in
width in a direction parallel to the plurality of second coupling axes,
the first structure group and the second structure group being coupled
with each other in such a manner that one of two end first structures of
the plurality of first structures, on a hand section side, and one of two
end second structures of the plurality of second structures, on the hand
section side, are coupled with each other, the robot arm supporting
member including drive means for (i) pressing the first structure group
and the second structure group so that the first structure group and the
second structure group become closer to each other and become in contact
with each other, (ii) causing the first structure group and the second
structure group to overlap each other so that a surface of the first
structure group and a surface of the second structure group, which
surfaces are in contact with each other, do not slip with respect to each
other, and (iii) driving the first structure group and the second
structure group in a direction in which the arm section is extensible, in
a case where the drive means causes the first structure group and the
second structure group to overlap each other, the first structure group
and the second structure group forming such a rigid arm section that
rotation of each of the plurality of first structures via the
corresponding one of the plurality of first coupling axes and rotation of
each of the plurality of second structures via the corresponding one of
the plurality of second coupling axes are prevented, at least one of the
first structure group and the second structure group is such that
adjacent ones of structures engage with each other via their side
surfaces, and form a plane surface having no gap, which plane surface
faces and is in contact with a surface of the other one of the first
structure group and the second structure group, the robot arm supporting
member including separation means in the robot arm supporting member, in
a case where the drive means carries out reverse driving, the separation
means causes the first structure group and the second structure group to
be separated from each other so that (i) each of the plurality of first
structures is rotatable around the corresponding one of the plurality of
first coupling axes and (ii) each of the plurality of second structures
is rotatable around the corresponding one of the plurality of second
coupling axes.

[0019] Additional objects, features, and strengths of the present
invention will be made clear by the description below. Further, the
advantages of the present invention will be evident from the following
explanation in reference to the drawings.

Advantageous Effects of Invention

[0020] As described above, a direct acting extensible and retractable arm
mechanism of the present invention includes: a robot arm supporting
member; a robot arm supporting member; and an arm section being
extensible and retractable directly from one of ends of the robot arm
supporting member, the arm section being such that a hand section is
attachable to one of ends of the arm section, the arm section being
constituted by (i) a first structure group in which a plurality of first
structures are coupled with each other in series in such a manner that
adjacent ones of the plurality of first structures are coupled with each
other via a corresponding one of a plurality of first coupling axes in a
direction which is orthogonal to a direction of the corresponding one of
the plurality of first coupling axes and (ii) a second structure group in
which a plurality of second structures are coupled with each other in
series in such a manner that adjacent ones of the plurality of second
structures are coupled with each other via a corresponding one of a
plurality of second coupling axes in a direction which is orthogonal to a
direction of the corresponding one of the plurality of second coupling
axes, the plurality of first structures being identical with each other
in width in a direction parallel to the plurality of first coupling axes,
the plurality of second structures being identical with each other in
width in a direction parallel to the plurality of second coupling axes,
the first structure group and the second structure group being coupled
with each other in such a manner that one of two end first structures of
the plurality of first structures, on a hand section side, and one of two
end second structures of the plurality of second structures, on the hand
section side, are coupled with each other, the robot arm supporting
member including drive means for (i) pressing the first structure group
and the second structure group so that the first structure group and the
second structure group become closer to each other and become in contact
with each other, (ii) causing the first structure group and the second
structure group to overlap each other so that a surface of the first
structure group and a surface of the second structure group, which
surfaces are in contact with each other, do not slip with respect to each
other, and (iii) driving the first structure group and the second
structure group in a direction in which the arm section is extensible, in
a case where the drive means causes the first structure group and the
second structure group to overlap each other, the first structure group
and the second structure group forming such a rigid arm section that
rotation of each of the plurality of first structures via the
corresponding one of the plurality of first coupling axes and rotation of
each of the plurality of second structures via the corresponding one of
the plurality of second coupling axes are prevented, at least one of the
first structure group and the second structure group is such that
adjacent ones of structures engage with each other via their side
surfaces, and form a plane surface having no gap, which plane surface
faces and is in contact with a surface of the other one of the first
structure group and the second structure group, the robot arm supporting
member including separation means in the robot arm supporting member, in
a case where the drive means carries out reverse driving, the separation
means causes the first structure group and the second structure group to
be separated from each other so that (i) each of the plurality of first
structures is rotatable around the corresponding one of the plurality of
first coupling axes and (ii) each of the plurality of second structures
is rotatable around the corresponding one of the plurality of second
coupling axes.

[0021] According to the arrangement, it is possible to provide a direct
acting extensible and retractable arm mechanism of a robot arm that (i)
can solve conventional problems that (1) it is difficult to ensure a high
rigidity for each of positions and postures of the direct acting
extensible and retractable arm mechanism, (2) it is difficult to prevent
a finger from being sandwiched inside the direct acting extensible and
retractable arm mechanism or dust from entering the direct acting
extensible and retractable arm mechanism, and (3) the direct acting
extensible and retractable arm mechanism has a large size when being
stored, and (ii) can be used in the vicinity of a human in a daily life
or the like.

BRIEF DESCRIPTION OF DRAWINGS

[0022] FIG. 1 is a perspective view illustrating an outer appearance of a
robot arm in accordance with an embodiment of the present invention.

[0023] FIG. 2 is a cross-sectional view partially illustrating a direct
acting extensible and retractable mechanism in accordance with the
embodiment of the present invention.

[0024] FIG. 3 is a perspective view illustrating an outer appearance of an
arrangement of a part of the direct acting extensible and retractable arm
mechanism in accordance with the embodiment of the present invention.

[0025]FIG. 4 is a perspective view illustrating an outer appearance of an
arrangement of a part of the direct acting extensible and retractable arm
mechanism in accordance with the embodiment of the present invention.

[0026]FIG. 5 is a perspective view illustrating an outer appearance of an
arrangement of a part of the direct acting extensible and retractable arm
mechanism in accordance with the embodiment of the present invention.

[0027]FIG. 6 is a perspective view illustrating an outer appearance of an
arrangement of a part of the direct acting extensible and retractable arm
mechanism in accordance with the embodiment of the present invention.

[0028] FIG. 7 is a cross-sectional view partially illustrating the direct
acting extensible and retractable arm mechanism in accordance with the
embodiment of the present invention.

[0029] FIG. 8 is a cross-sectional view illustrating a modified example of
the direct acting extensible and retractable arm mechanism in accordance
with the embodiment of the present invention.

[0030] FIG. 9 is a cross-sectional view illustrating a modified example of
the direct acting extensible and retractable arm mechanism in accordance
with the embodiment of the present invention.

[0031] FIG. 10 is a cross-sectional view illustrating a modified example
of the direct acting extensible and retractable arm mechanism in
accordance with the embodiment of the present invention.

[0032]FIG. 11 is a cross-sectional view illustrating a modified example
of the direct acting extensible and retractable arm mechanism in
accordance with the embodiment of the present invention.

[0033] FIG. 12 is a cross-sectional view illustrating a modified example
of the direct acting extensible and retractable arm mechanism in
accordance with the embodiment of the present invention.

[0034] FIG. 13 is a cross-sectional view illustrating a modified example
of the direct acting extensible and retractable arm mechanism in
accordance with the embodiment of the present invention.

[0035] FIG. 14 is a cross-sectional view illustrating a modified example
of the direct acting extensible and retractable arm mechanism in
accordance with the embodiment of the present invention.

[0036] FIG. 15 is a cross-sectional view illustrating a modified example
of the direct acting extensible and retractable arm mechanism in
accordance with the embodiment of the present invention.

[0037] FIG. 16 is a cross-sectional view illustrating a modified example
of the direct acting extensible and retractable arm mechanism in
accordance with the embodiment of the present invention.

[0038]FIG. 17 is a view illustrating a modified example of the direct
acting extensible and retractable arm mechanism in accordance with the
embodiment of the present invention: (a) of FIG. 17 is a top view; and
(b) of FIG. 17 is a front view.

[0039] FIG. 18 is a cross-sectional view illustrating a modified example
of the direct acting extensible and retractable arm mechanism in
accordance with the embodiment of the present invention.

[0040] FIG. 19 is a view illustrating a conventional arrangement.

DESCRIPTION OF EMBODIMENTS

[0041] A direct acting extensible and retractable arm mechanism of the
present invention can (i) ensure a high rigidity for all positions and
all postures of an arm section which is extensible and retractable
directly from one of ends of a robot arm supporting member, (ii) prevent
a finger or the like from being sandwiched or prevent dust from entering
the arm section, and (iii) have a reduction in size when being stored.
For these reasons, the direct acting extensible and retractable arm
mechanism can be applied not only to a robot arm for supporting safely a
daily life of a handicapped person or a daily life of an aged person, in
the vicinity of that person, but also to, for example, a next-generation
robot arm for cellular manufacturing, which operates in cooperation with
a human.

[0042] One embodiment of the present invention is described below with
reference to FIGS. 1 through 10. Note that the entire direct acting
extensible and retractable arm mechanism may be regarded as a single
operational joint, and may be referred to as "direct acting extensible
and retractable arm joint J3", in some cases.

[0043] FIG. 1 is a perspective view illustrating an outer appearance of a
robot arm, which is one embodiment of the direct acting extensible and
retractable arm mechanism of the present invention.

[0046] The robot arm supporting member 1 has a structure that extends,
from an installation surface G on which the robot arm 50 is installed, in
a direction vertical to the installation surface G. The robot arm
supporting member 1 supports the entire robot arm 50 (see FIG. 1).

[0047] The robot arm supporting member 1 includes a first supporting
section 10a, a second supporting section 10b, a third supporting section
10c, a first rotational joint J1 (rotational joint means), and a second
rotational joint J2 (see FIG. 1).

[0048] The first supporting section 10a and the second supporting section
10b have a hollowed shape (see FIG. 1). The first supporting section 10a
and the second supporting section 10b are arranged in a lower position
and an upper position, respectively, so that a center axis (supporting
axis) of the first supporting section 10a and a center axis (supporting
axis) of the second supporting section 10b match each other. The third
supporting section 10c also has a hollowed structure, which is in
communication with both the hollowed structure of the first supporting
section 10a and the hollowed structure of the second supporting section
10b. A part of constituent elements of the arm section 2 (later
described) is arranged so as to be storable inside these sections, that
is, the first supporting section 10a, the second supporting section 10b,
and the third supporting section 10c.

[0049] The first rotational joint J1 is provided between the first
supporting section 10a and the second supporting section 10b, and is
constituted as a rotational joint whose rotational axis is a center axis
(the center axis of the first supporting section 10a and the center axis
of the second supporting section 10b) of the robot arm supporting member
1. Rotation of the first rotational joint J1 causes the second supporting
section 10b, the third supporting section 10c, the arm section 2, and the
hand section 3 to be rotated around the rotational axis of the first
rotational joint J1.

[0050] The second rotational joint J2 is provided at one of ends of the
second supporting section 10b on an arm section 2 side (see FIG. 1), and
is constituted as a rotational joint whose rotational axis is orthogonal
to the axis of the robot arm supporting member 1. Rotation of the second
rotational joint J2 causes the third supporting section 10c, the arm
section 2, and the hand section 3 to be rotated around the rotational
axis of the second rotational joint J2 with respect to the robot arm
supporting member 1. Further, the second rotational joint J2 has a
certain angle and a certain distance from the center axis of the robot
arm supporting member 1 so that an object located around the robot arm 50
would not be tightly sandwiched between the robot arm supporting member 1
and the arm section 2.

[0051] According to the present embodiment, the robot arm supporting
member 1 extends from the installation surface G in the direction
vertical to the installation surface G. Note, however, that the present
invention is not limited to this, as long as the robot arm supporting
member 1 extends from the installation surface G while having a certain
angle with respect to the installation surface G.

[0052] [Hand Section]

[0053] The hand section 3 is provided at one of ends of the arm section 2.
The hand section 3 includes a fourth rotational joint J4, a fifth
rotational joint J5, a sixth rotational joint J6, a seventh rotational
joint J7, a first finger 70, and a second finger 71 (see FIG. 1). Note
that the first finger 70 and the second finger 71 constitute a two-finger
hand 72.

[0054] The fourth rotational joint J4 is a rotational joint whose rotation
axis is a center axis (hereinafter, referred to as "arm axis", in some
cases) of the arm section 2, which center axis extends in a direction in
which the arm section 2 is extensible and retractable. Rotation of the
fourth rotational joint J4 causes the hand section 3 (a part from one of
ends of the hand section 3, i.e., the fourth rotational joint J4, to the
other one of ends of the hand section 3) to be rotated around the
rotational axis of the fourth rotational joint J4.

[0055] The fifth rotational joint J5 is a rotational joint whose
rotational axis is orthogonal to the arm axis. Rotation of the fifth
rotational joint J5 causes the two-finger hand 72 (a part from one of
ends of the fifth rotational joint J5 to the other one of ends of the
hand section 3) to be rotated around the rotational axis of the fifth
rotational joint J5.

[0056] The sixth rotational joint J6 is a rotational joint whose
rotational axis is orthogonal to both the arm axis and the fifth
rotational joint J5. Rotation of the sixth rotational joint J6 causes the
two-finger hand 72 to be rotated around the rotational axis of the sixth
rotational joint J6. Here, the first finger 70 and the second finger 71
keep a distance between these, and are rotated, in synchronization with
each other, around the rotational axis of the sixth rotational joint J6.

[0057] The seventh rotational joint J7 causes the first finger 70 and the
second finger 71 of the two-finger hand 72 to be rotated. That is, the
seventh rotational joint J7 can cause one of ends of the first finger 70
and one of ends of the second finger 71 to be rotated, and therefore to
be close to each other. In this case, the two-finger hand 72 is closed so
as to hold an object. On the other hand, the seventh rotational joint J7
can cause the one of ends of the first finger 70 and the one of ends of
the second finger 71 to be rotated, and therefore to be away from each
other. In this case, the two-finger hand 72 is opened so as to release
the object held by the two-finger hand 72.

[0058] According to the present embodiment, the two-finger hand 72 is used
as the hand section 3. Note, however, that the present invention is not
limited to this, and the hand section 3 may be a hand having not less
than three fingers. Further, the hand section 3 is not limited to a hand
having a finger section(s), and any desired sorts of structure, required
to be at a desired position or to have a desired posture by use of the
arm section, can be connected to the arm section in place of the hand
section 3. For example, it is possible to connect a device having an
image capturing function to the arm section, in place of the hand section
3.

[0059] Note that the scope of the direct acting extensible and retractable
arm mechanism of the present invention also encompasses an arrangement in
which the hand section 3 is not connected.

[0060] [Arm Section]

[0061] The arm section 2 includes a direct acting extensible and
retractable arm joint J3 illustrated in FIG. 1. The hand section 3 is
provided at one of ends of the arm section 2. The hand section 3 is
provided with the two-finger hand 72. The robot arm supporting member 1,
the arm section 2, and the hand section 3 can cause, in cooperation with
each other, the two-finger hand 72 to be moved to a desired position or
moved to have a desired posture. In a state illustrated in FIG. 1, the
direct acting extensible and retractable arm joint J3 can be extended so
as to cause the two-finger hand 72 to be moved to a position away from
the robot arm supporting member 1. Alternatively, the direct acting
extensible and retractable arm joint J3 can be retracted so as to cause
the two-finger hand 72, which is located away from the robot arm
supporting member 1, to be moved to be closer to the robot arm supporting
member 1.

[0062] FIG. 2 is a fragmentary cross-sectional view partially illustrating
the robot arm 50, taken along a cutting line of A-A' shown in FIG. 1.

[0063] As illustrated in FIG. 2, the arm section 2 is mainly constituted
by (i) an upper structure group 20 and a lower structure group 21, which
constitute the direct acting extensible and retractable arm joint J3, and
(ii) drive means 40 (drive mechanism) for driving the direct acting
extensible and retractable arm joint J3.

[0064] The direct acting extensible and retractable arm joint J3 can
constitute the arm section 2 that (i) is stored in the robot arm
supporting member 1 extending, from the installation surface 50 on which
the robot arm 50 is installed, in the direction vertical to the
installation surface 50, and (ii) is extensible from the robot arm
supporting member 1 via the third supporting section 10c (see FIG. 1).
Here, the direct acting extensible and retractable arm joint J3 is
arranged such that the lower structure group 20 is provided at a lower
position with respect to the upper structure group 20 in a direction of
gravitational force. Overlapping of the upper structure group 20 and the
lower structure group 21 causes both the upper structure group 20 and the
lower structure group 21 to become rigid, so that the upper structure
group 20 and the lower structure group 21 form the arm section 2. The
second rotational joint J2 causes the arm section 2 to be rotated around
the second rotational joint J2.

[0065] (Common Block Member)

[0066] A common block member 60 is attached to both (i) one of ends of the
upper structure group 20 and (ii) one of ends of the lower structure
group 21 (see FIGS. 2, 3, 5, and 7). An upper structure 22, provided
adjacent to the common block member 60, is coupled with the common block
member 60. A lower structure 23, provided adjacent to the common block
member 60, is also coupled with the common block member 60. The common
block member 60 has such a shape that a single upper structure 22 and a
single lower structure 23 are formed integral with each other.

[0067] According to the present embodiment, the common block member 60 has
such an integral shape. Note, however, that the present invention is not
limited to this, as long as the one of ends of the upper structure group
20 and the one of ends of the lower structure group 21 are not away from
each other inconveniently in an extending/retracting operation of the
direct acting extensible and retractable arm joint J3. Accordingly, it is
possible to employ, as the common block member 60, not only the
aforementioned member but also such a member that a single upper
structure 22 and a single lower structure 23 are attached to each other
by use of an adhesive or by welding. Furthermore, it is also possible to
employ, as the common block member 60, such a member that a single upper
structure 22 and a single lower structure 23 are formed integral with
each other by use of a fixing mechanism. Moreover, it is also possible to
employ, as the common block member 60, such a member that a single upper
structure 22 and a single lower structure 23 are not attached to each
other but are pressed with respect to each other to be in contact with
each other, and are covered with a cover case.

[0068] According to the present embodiment, the common block member 60 has
such a shape that the upper structure 22 and the lower structure 23 are
formed integral with each other. Note, however, that the present
invention is not limited to this. In a case where it is unnecessary to
store the common block member 60 in the robot arm supporting member 1 via
the third supporting section 10c, it is possible that both the one of
ends of the upper structure group 20 and the one of ends of the lower
structure group 21 are formed integral with each other, and are connected
to a common block member 60 having an arbitrary shape.

[0069] Lower Structure Group

[0070] The lower structure group 21 is constituted by a plurality of lower
structures 23 (see FIG. 2). All the plurality of structures 23 are
connected to each other in series (from one of two end lower structures
23 to the other one of two end lower structures 23).

[0071] Further, adjacent ones of the plurality of lower structures 23 are
coupled with each other via a rotational axis (coupling axis) (later
described) in a direction orthogonal to the rotational axis. Furthermore,
the plurality of lower structures 23 are identical with each other in
size (width) in a direction parallel to the coupling axis.

[0072] The following description deals with details of each of coupling
parts of the lower structure group 21 and details of an arrangement of
each of the plurality of lower structures 23, with reference to FIGS. 3
and 4. FIG. 3 is a perspective view illustrating an outer appearance of a
part of the lower structure group 21. Further, FIG. 4 is a perspective
view illustrating an outer appearance of a single lower structure 23.

[0073] First, the following description deals with a coupling part of the
lower structure group 21. Adjacent ones of the plurality of lower
structures 23 are coupled with each other via a rotational axis, e.g., a
bearing employing a pin 30. Specifically, a lower structure 23 has a
through hole 25 at a coupling part between the lower structure 23 and one
of adjacent lower structures 23, and a through hole 26 at another
coupling part between the lower structure 23 and the other one of the
adjacent lower structures 23. Both the thorough hole 25a and the through
hole 25b extend in a direction vertical to a coupling direction. Adjacent
ones of the plurality of lower structures 23, each having the above
structure, are coupled with each other such that a through hole 25a of
one of the adjacent ones of the plurality of lower structures 23 and a
through hole 25b of the other one of the adjacent ones of the plurality
of lower structures 23 are coupled with each other. That is, the through
hole 25a of the one of the adjacent ones of the plurality of lower
structures 23 and the through hole 25b of the other one of the adjacent
ones of the plurality of lower structures 23 form, in cooperation with
each other, a single through hole. A single pin 30 is inserted into the
single through hole so that the adjacent ones of the plurality of lower
structures 23 are coupled with each other. According to the present
embodiment, the coupling part between adjacent ones of the plurality of
lower structures 23 is such that (i) one of ends of one of the adjacent
ones of the plurality of lower structures 23 has a convex structure
having a through hole 25b, (ii) one of ends of the other one of the
adjacent ones of the plurality of lower structures 23 has a concave
structure having a through hole 25a, and (iii) the convex structure
engages with the concave structure so as to form a single through hole
(see FIG. 4). Note, however, that the present invention is not limited to
this coupling method.

[0074] Next, the following description deals with a structure of each of
the plurality of lower structures 23. As illustrated in FIGS. 3 and 4,
each of the plurality of lower structures 23 is such that, in a case
where the lower structure 23 is cut along a plane vertical to a
longitudinal direction, a cross-section of the lower structure 23 has a
concave shape (where "longitudinal direction" is a direction in which
adjacent ones of the plurality of lower structures 23 are coupled with
each other, as described later). In the present specification, an opened
part of the concave shape is referred to as "opening section". Further, a
surface having the opening section is referred to as "upper surface" of
the lower structure 23, in some cases. The upper surface indicates a
surface which is located at an upper position in the direction of
gravitational force, in a case where the adjacent ones of the plurality
of lower structures 23 are coupled with each other in a horizontal
direction.

[0075] Under a condition that the adjacent ones of the plurality of lower
structures 23 are coupled with each other and arranged linearly, opening
sections of the adjacent ones of the plurality of lower structures 23 are
also coupled with each other, and therefore form such a single groove
that structures having the concave shape are connected to each other. An
inner space of the groove can be used effectively as a space in which an
electrical line is provided along the groove.

[0076] Note that, in a case where it is unnecessary to obtain such an
inner space of the groove, it is possible that each of the plurality of
lower structures 23 has not such a groove structure but a general block
structure.

[0077] Further, surfaces of adjacent ones of the plurality of lower
structures 23, which surfaces face each other, can have, respectively,
side surface convex-concave structures 23a (alignment sections) which
engage with each other (see FIG. 9). A side surface convex-concave
structure 23a of one of adjacent ones of the plurality of lower
structures 23 engages with a side surface convex-concave structure 23a of
the other one of the adjacent ones of the plurality of lower structures
23, so that the adjacent ones of the plurality of lower structures 23 can
be prevented significantly from being out of alignment in a coupling
direction, at a coupling part between the adjacent ones of the plurality
of lower structures 23, due to rotation around a rotational axis in the
coupling direction (see FIG. 9). This makes it possible to further
increase a rigidity of a combined structure of an upper structure and a
lower structure.

[0078] Furthermore, since the surfaces of the adjacent ones of the
plurality of lower structures 23, which surfaces face each other, have
side surfaces 23b, respectively. Since the side surfaces 23b are
provided, it is possible to prevent the adjacent ones of the plurality of
lower structures 23 from being changed from (i) a state where the
adjacent ones of the plurality of lower structures 23 are arranged to be
connected to each other in series while concave opening sections of the
adjacent ones of the plurality of lower structures 23 face in the same
direction to (ii) a state where the adjacent ones of the plurality of
lower structures 23 are rotated to form a V shape while the concave
opening sections faces "inward" with respect to each other.

[0079] Meanwhile, it is possible to cause the adjacent ones of the
plurality of lower structures 23 to be changed from (i) the state where
the adjacent ones of the plurality of lower structures 23 are arranged to
be connected to each other in series while concave opening sections of
the adjacent ones of the plurality of lower structures 23 face in the
same direction to (ii) a state where the adjacent ones of the plurality
of lower structures 23 are rotated to form a V shape while the concave
opening sections of the adjacent ones of the plurality of lower
structures 23 face "outward" with respect to each other.

[0080] Moreover, it is possible that (i) adjacent ones of the plurality of
lower structures 23 of the lower structure group 21 engage with each
other via their side surfaces, and therefore (ii) a surface of the lower
structure group 21, which surface faces the upper structure group 20,
becomes a plane surface having no gap. This arrangement can (i) prevent
an object from being sandwiched between adjacent ones of the plurality of
lower structures 23 and (ii) prevent dust from entering a space between
adjacent ones of the plurality of lower structures 23.

[0081] Further, an edge section is formed around each of opening sections
of the plurality of lower structures 23, and is in contact with the upper
structure group 22 (later described). The edge section has an upper
surface convex-concave structure 23c (engaging section) (see FIG. 9). The
upper surface convex-concave structure 23c is arranged so as to engage
with a bottom surface convex-concave structure 22a of each of the
plurality of upper structures 22 (later described) (see FIG. 10).

[0082] Note that, in a case where a gear roller is attached, as a pressing
roller 41, to a bottom surface of a part where the plurality of lower
structures 23 of the lower structure group 21 are arranged to be
connected to each other in series in the horizontal direction, or in a
case where an arrangement which is the same as a gear 34 is provided in
place of the pressing roller 41, a bottom surface convex-concave
structure 23d which engages with such a gear is provided on the bottom
surface of each of the plurality of lower structures 23.

[0083] Upper Structure Group

[0084] The upper structure group 20 is constituted by plurality of upper
structures 22 (see FIG. 2). All the plurality of upper structures 22 are
connected to each other in series (from one of two end upper structures
22 to the other one of two end upper structures 22).

[0085] Further, adjacent ones of the plurality of upper structures 22 are
coupled with each other via a rotational axis (coupling axis) (later
described) in a direction orthogonal to the rotational axis. Furthermore,
the plurality of upper structures 22 are identical with each other in
size (width) in a direction parallel to the coupling axis.

[0086] The following description deals with details of a coupling part of
adjacent ones of the plurality of upper structures 22, and an arrangement
of each of the plurality of upper structures 22, with reference to FIGS.
5 and 6. FIG. 5 is a perspective view illustrating an outer appearance of
a part of the plurality of upper structures 22. Moreover, FIG. 6 is a
perspective view illustrating an outer appearance of a single upper
structure 22.

[0087] First, the following description deals with each of coupling parts
of the upper structure group 20. Adjacent ones of the plurality of upper
structures 22 are coupled with each other via a rotational axis, such as
a bearing employing a pin 31 (see FIG. 5). Specifically, each of the
plurality of upper structures 22 has such a structure that (i) a part of
the upper structure 22, which part is adjacent to one of adjacent
structures 22, has a through hole 24a, (ii) another part of the upper
structure 22, which another part is adjacent to the other one of adjacent
upper structure 22, has a through hole 24b, and (iii) both the through
hole 24a and the through hole 24b extend in a direction vertical to the
coupling direction. A through hole 24a of one of adjacent ones of the
plurality of upper structures 22 and a through hole 24b of the other one
of adjacent ones of the plurality of upper structures 22 engage with each
other, so as to form a single through hole. A single pin 31 is inserted
into the single through hole, so that the adjacent ones of the plurality
of upper structures 22 are coupled with each other. According to the
present embodiment, the coupling part between adjacent ones of the
plurality of upper structures 22 is such that (i) a part of one of the
adjacent ones of the plurality of upper structures 22, which part is
adjacent to the other one of the adjacent ones of the plurality of upper
structures 22, has a convex structure having a through hole 24a, and (ii)
a part of the other one of the adjacent ones of the plurality of upper
structures 22, which part is adjacent to the one of the adjacent ones of
the plurality of upper structures 22, has a concave structure having a
through hole 24b (see FIG. 6). The convex structure engages with the
concave structure so as to form a single through hole. Note, however,
that the present invention is not limited to this coupling method.

[0088] Adjacent ones of the plurality of upper structures 22, coupled with
each other, are rotatable with respect to each other around the pin 31
(see FIG. 5) serving as a rotational axis.

[0089] Each of the plurality of upper structures 22 has a side surface 22b
which faces an adjacent upper structure 22 (see FIG. 6). The provision of
the side surface 22b makes it possible that the adjacent ones of the
plurality of upper structures 22 are changed from (i) a state where the
adjacent ones of the plurality of upper structures 22 are arranged to be
connected to each other in series to (ii) a state where one of the
adjacent ones of the plurality of upper structures 22 is rotatable with
respect to the other one of the adjacent ones of the plurality of upper
structures 22 in such a range that the adjacent ones of the plurality of
upper structures 22 form a V shape in a direction opposite to the
direction of gravitational force.

[0090] Meanwhile, the adjacent ones of the plurality of upper structures
22 is not changed from (i) the state where the adjacent ones of the
plurality of upper structures 22 are arranged to be connected to each
other in series to (ii) a state where the adjacent ones of the plurality
of upper structures 22 form a V shape in the direction of gravitational
force.

[0091] Accordingly, the adjacent ones of the plurality of upper structures
22 of the upper structure group 20 engage with each other via their side
surfaces, so that a surface of the upper structure group 20, which
surface faces and in contact with a surface of the lower structure group
21, becomes a plane surface having no gap. For this reason, it is
possible to (i) prevent an abject from being sandwiched between adjacent
ones of the plurality of upper structures 22, and (ii) prevent dust from
entering a space between adjacent ones of the plurality of upper
structures 22. Further, it is possible to increase a rigidity of the arm
section 2.

[0092] Furthermore, a range of rotational movement of the plurality of
upper structures 22 is not limited to the range described above, in a
case where a reduction in a property of preventing entry of dust and a
reduction in rigidity are accepted.

[0093] Next, the following description deals with an arrangement of each
of the plurality of upper structures 22. As illustrated in FIGS. 5 and 6,
each of the plurality of upper structures 22 generally has a plate shape,
and has a through hole 24a at one of ends of the upper structure 22, and
through hole 24b at the other one of ends of the upper structure 22, as
described above. In a case where a direction in which adjacent ones of
the plurality of upper structures 22 are coupled with each other is
referred to as "longitudinal direction" (as described below), a single
upper structure 22 has the through hole 24a at one of its ends in the
longitudinal direction and the through hole 24b at the other one of its
ends in the longitudinal direction.

[0094] Furthermore, it is possible that a bottom surface of each of the
plurality of upper structures 22 has a bottom surface convex-concave
structure 22a, which engages with an upper surface convex-concave
structures 23c provided on an upper surface of a corresponding one of the
plurality of lower structures 23 (see FIG. 10). In this case, it is
possible to (i) prevent significantly an upper structure 22 and a lower
structure 23 from being out of alignment with respect to each other in
the coupling direction and (ii) further increase a rigidity of a combined
structure of the upper structure 22 and the lower structure 23.

[0095] Note that, in a case where a gear roller is provided, as a pressing
roller 42 (later described), on an upper surface of a part where the
plurality of upper structures 22 of the upper structure group 20 are
arranged to be connected to each other in series in the horizontal
direction, or in a case where an arrangement which is the same as the
gear 34 (not illustrated) is provided in place of the pressing roller 42,
an upper surface convex-concave structure which engages with such a gear
can be formed on the upper surface of each of the plurality of upper
structures 22.

[0096] Drive Means

[0097] The drive means 40 has the following functions: (1) forming a
combined structure of the plurality of upper structures 22 and the
plurality of lower structures 23, which structure extends directly and is
rigid; and (2) releasing such a direct rigid combined structure. The
above (1) is obtained in such a manner that the lower structure group 21,
in which adjacent ones of the plurality of lower structures 23 are in
contact with each other, coupled with each other via their side surfaces
23b (illustrated in FIGS. 4 and 7), and arranged in the horizontal
direction, is arranged under the upper structure group 20, in which
adjacent ones of the plurality of upper structures 22 are in contact with
each other, coupled with each other via their side surfaces 22b
(illustrated in FIG. 6), and are arranged in the horizontal direction.
The above (2) is obtained in such a manner that the upper structure group
20 of the direct rigid combined structure of the plurality of upper
structures 22 and the plurality of lower structures 23 is detached from
the lower structure group 21 which is provided adjacent to the upper
structure group 20.

[0098] With such functions, the rigid combined structure of the plurality
of upper structures 22 and the plurality of lower structures 23,
connected in series, is realized as the arm section 2 protruding from an
opening section 10c' illustrated in FIG. 7, and can change its length
(extension and retraction of the direct acting extensible and retractable
joint J3) arbitrarily. Hereinafter, a length of a part of the combined
structure of the plurality of upper structures 22 and the plurality of
lower structures 23, which part protrudes from the opening section 10c',
is referred to as "arm length", in some cases.

[0100] Note that, in place of the arrangement employing the drive means
40a for causing the lower structure group to operate and the separation
means 40c, the drive means 40 can have an arrangement employing drive
means 40b (see FIG. 7) for causing the upper structure group 20 to
operate and the separation means 40c.

[0101] Further, in order to cause operations of the upper structure group
20 and the lower structure group 21 to be in synchronization with each
other completely, the drive means 40 can include all of the drive means
40a for the lower structure group, the drive means 40b for the upper
structure group, and the separation means 40c.

[0102] The drive means 40a for the lower structure group is provided in
the vicinity of the opening section 10c' of the third supporting section
10c so as to cause the lower structure group 21 to move in an axial
direction. The following description deals with details of the drive
means 40a for the lower structure group with reference to FIG. 7. The
drive means 40a for the lower structure group includes a gear 34 which
engages with a bottom surface convex-concave structure 23a of each of the
plurality of lower structures 23, and a drive mechanism 33 which is
constituted by an actuator 35 for driving the gear 34 (see FIG. 7).

[0103] Furthermore, the drive means 40a for the lower structure group can
include a pressing roller (pressing member) 41.

[0104] The drive means 40b for the upper structure group is provided in
the vicinity of the opening section 10c' of the third supporting section
10c so as to cause the upper structure group 20 to move in the axial
direction. The following description deals with details of the drive
means 40b for the upper structure group. The drive means 40b for the
upper structure group includes a gear which engages with an upper surface
convex-concave structure of each of the plurality of upper structures 22,
and a drive mechanism which is constituted by an actuator for driving the
gear. Further, the drive means 40b for the upper structure group can
include a pressing roller (pressing member) 42.

[0105] Note that, in place of the arrangement described above, the drive
mechanism 33 can have an arrangement employing (i) a worm gear reducer
constituted by a combination of the bottom surface convex-concave
structure 23b of each of the plurality of lower structures 23 and a worm
gear, and (ii) an actuator for driving the worm gear. Alternately, in
place of the arrangement described above, the drive mechanism
constituting the drive means 40b for the upper structure group can have
an arrangement employing (i) a worm gear reducer constituted by a
combination of the upper surface convex-concave structure of each of the
plurality of upper structures 22 and a worm gear, and (ii) an actuator
for driving the worm gear. According to such an arrangement, it is
possible to achieve a large gear ratio with the use of gears the number
of which is significantly smaller (several gears) than the number of
gears of a gear reducer employing general spur gears. It is therefore
possible to realize a gear reducer having a significantly compact body.
Further, this arrangement has no back drivability. For this reason, the
arm section 2 is operated only by the actuator 35, and even if external
force is provided to operate the arm section 2, the arm section 2 would
not be operated.

[0106] As illustrated in FIG. 7, the pressing roller (pressing member) 41
of the drive means 40a for the lower structure group is provided to be
closer to the opening section 10c' of the third supporting section, as
compared with the drive mechanism 33. The pressing roller 41 (i) presses,
in a direction opposite to the direction of gravitational force, a bottom
surface of the lower structure group 21 (lower structures 23) which is
linearly arranged and is to be outputted by the drive mechanism 33 from
the opening section 10c', and (ii) outputs the lower structure group 21
to the outside from the opening section 10c'.

[0107] Furthermore, the pressing roller (pressing member) 42 of the drive
means 40b for the upper structure group is also provided to be closer to
the opening section 10c' of the third supporting section 10c, as compared
with the drive mechanism. The pressing roller 42 (i) presses, in the
direction of gravitational force, an upper surface of the upper structure
group 20 (the upper structures 22) which is linearly arranged and is to
be outputted from the opening section 10c' by the drive mechanism, and
(ii) outputs the upper structure group 20 from the opening section 10c'
to the outside.

[0108] The rigid combined structure of the plurality of upper structures
22 and the plurality of lower structures 23, i.e., the arm section, is
established in such a manner that the plurality of upper structures 22
and the plurality of lower structures 23 are pressed with respect to each
other (in overlapping directions) by use of the pressing roller 41 and
the pressing roller 42 and, as a result, are in contact with each other.

[0109] Note that the arm section can be held by the pressing roller 42 and
the gear 34 for driving the plurality of lower structures 23.

[0110] Further, the arm section can be held by the pressing roller 41 and
the gear for driving the plurality of upper structures 22.

[0111] Furthermore, the arm section can be held by the gear for driving
the plurality of upper structures 22 and the gear 34 for driving the
plurality of lower structures 23. Moreover, the arm section can be held
by the pressing roller 41, the pressing roller 42, and the gear 34 for
driving the plurality of lower structures 23.

[0112] Further, the arm section can be held by the pressing roller 41, the
pressing roller 42, and the gear for driving the plurality of upper
structures 22.

[0113] Furthermore, the arm section can be held by the pressing roller 41,
the gear for driving the plurality of upper structures 22, and the gear
34 for driving the plurality of lower structures 23.

[0114] Moreover, the arm section can be held by the pressing roller 42,
the gear for driving the plurality of upper structures 22, and the gear
34 for driving the plurality of lower structures 23.

[0115] A mechanism of each of the pressing roller 41 is not particularly
limited. However, as an example, the pressing roller has an arrangement
in which an elastic member such as a spring is additionally attached to a
rotational axis of a roller.

[0116] Two pressing rollers 41 are provided along the upper structure
group 20 in FIG. 7. Note, however, that the number of pressing rollers 41
is not limited to this.

[0117] Further, in the present embodiment, as illustrated in FIGS. 2 and
7, the two pressing rollers 41 of the drive means 40a for the lower
structure group are provided to be closer to the opening section 10c', as
compared with the drive mechanism 33 of the drive means 40a for the lower
structure group. Note, however, that the present invention is not limited
to this. The drive mechanism 33 can be provided to be closer to the
opening section 10c' than the two pressing rollers 41 are.

[0118] Next, the drive means 40b for the upper structure group is provided
in the vicinity of the opening section 10c' of the third supporting
section 10c, so as to cause the upper structure group 20 to be moved. The
drive means 40b for the upper structure group includes the pressing
roller (pressing members) 42. The pressing roller 42 can press the upper
structure group 20 (upper structures 22) in the direction of
gravitational force. A mechanism of the pressing rollers 42 is not
particularly limited. However, as an example, the pressing roller 42 can
have an arrangement in which an elastic member such as a spring is
additionally attached to a rotational axis of a pressing roller.

[0119] Three pressing rollers 42 are provided along the upper structure
group 20 in FIGS. 2 and 7. Note, however, that the number of pressing
rollers 42 is not limited to this.

[0120] Further, in addition to the three pressing rollers 42, it is also
possible to provide, in a position opposite to an upper surface of the
upper structure group 20, a member having the same arrangement as that of
the drive mechanism 33 of the drive means 40a for the lower structure
group. In this case, the upper surface of the upper structure group 20
has the upper surface convex-concave structure.

[0121] The following description deals with, with reference to FIG. 7, (i)
how the upper structure group 20 and the lower structure group 21 are
combined with each other by driving carried out by the drive means 33 and
(ii) how the direct rigid combined (pressed) structure of the plurality
of upper structures 22 and the plurality of lower structures 23 is
formed.

[0122] As described above, the upper structure group 20 is such that the
plurality of upper structures 22 are arranged to be connected to each
other in series, and the lower structure group 21 is such that the
plurality of lower structures 23 are arranged to be connected to each
other in series. In a case where positions of coupling axes of the upper
structure group 20 and positions of coupling axes of the lower structure
group 21 correspond to each other in the longitudinal direction (as
illustrated in FIGS. 2 and 7), that is, in a case where, in the arm
section in which both of the upper structure group 20 and the lower
structure group 21 are rigid, the coupling axes of the lower structure
group 21 are positioned below the respective coupling axes of the upper
structure group 20 in the direction of gravitational force, (i) the upper
structure group 20 and the lower structure group 21 are supported in a
position close to the opening section 10c' of the third supporting
section 10c, and (ii) one of ends of the upper structure group 20 and one
of ends of the lower structure group 21 are connected to a common block
member 60. It is thus possible to realize such a rigid state of the arm
section 2.

[0123] The present invention is not limited to the arrangement in which
the coupling axes of the lower structure group 21 are positioned below
the respective coupling axes of the upper structure group 20 in the
direction of gravitational force. It is also possible to have such an
arrangement that each the coupling axes of the plurality of upper
structures 22 is provided in the vicinity of a center of a corresponding
one of the plurality of lower structures 23 and each of the coupling axes
of the plurality of lower structures 23 are provided in the vicinity of a
center of a corresponding one of the plurality of upper structures 22
(see FIG. 8), that is, in the arm section in which both the upper
structure group 20 and the lower structure group 21 are rigid, each of
the coupling axes of the lower structure group is provided below a space
between adjacent ones of the coupling axes of the upper structure group
20 in the direction of gravitational force. In this case, it is possible
to prevent successfully both the plurality of upper structures 22 of the
upper structure group 20 and the plurality of lower structures 23 of the
lower structure group 21 from being flexed and rotated. This makes it
possible to cause the combined structure to have a greater rigidity.

[0124] (Storage of Arm Section)

[0125] Most of the rigid combined structure of the plurality of upper
structures 22 and the plurality of lower structures 23, that is, most of
the arm section, protrudes from the opening section 10c' of the third
supporting section 10c to an outside in the axial direction. Meanwhile, a
part of the upper structure group 20 and a part of the lower structure
group 21, both of which do not constitute the rigid combined structure,
are (i) arranged to be curved along a shape of the robot arm supporting
member 1 (see FIG. 1), and are (ii) stored inside inner space of the
robot arm supporting member 1.

[0126] In order to retract an extended combined structure of the plurality
of upper structures 22 and the plurality of lower structures 23, the gear
34 of the drive mechanism 33 is rotated so as to retract the combined
structure of the plurality of upper structures 22 and the plurality of
lower structures 23 into an inside of the third supporting section 10c.
Inside the third supporting section 10c, the separation means 40c is
provided at a position sandwiched between the upper structure group 20
and the lower structure group 21 (see FIGS. 2 and 7). The combined
structure of the plurality of upper structures 22 and the plurality of
lower structures 23 is retracted into the inner space of the third
supporting section 10c, so that a combined part of the combined structure
is released by insertion of the separation means 40c into the combined
part. The combined structure is thus separated into two parts. By further
retracting the combined structure of the plurality of upper structures 22
and the plurality of lower structures 23 into the inside of the third
supporting section 10c, the upper structure group 20 and the lower
structure group 21 are moved from the third supporting section 10c to the
second supporting section 10b, and then are stored in the first
supporting section 10a.

[0127] In a case where the combined structure of the plurality of upper
structures 22 and the plurality of lower structures 23 is stored, the
upper structure group 20 separated by the separation means 40c is moved
above the separation means 40c. The upper structure group 20 thus
separated is such that each of the plurality of upper structures 20 can
rotate around a pin 30 serving as a rotational axis. Accordingly, the
upper structure group 20 is stored in the arm supporting member 1 along a
shape of the arm supporting member 1. The lower structure group 21 thus
separated is such that each of the plurality of lower structures 21 can
rotate around a pin serving as a rotational axis. Accordingly, the lower
structure group 21 is stored in the arm supporting member 1 along the
shape of the arm supporting member 1. As such, since both the upper
structure group 20 and the lower structure group 21 can be stored in the
arm supporting member 1 along the shape of the arm supporting member 1,
it is possible to have a reduction in size of the arm section 2 in a case
where the arm section 2 is stored.

[0128] (Condition for Rigid Structure of Arm Section)

[0129] According to the present embodiment, as illustrated in FIGS. 2 and
7, the rigid structure of the arm section 2 is realized on the following
conditions (i) through (iv): (i) one of ends of the upper structure group
20 and one of ends of the lower structure group 21 are connected to the
common block member 60, (ii) a part of the upper structure group 20,
protruding from the opening section 10c' of the third supporting section
10c to the outside, and a part of the lower structure group 21,
protruding from the opening section 10c' to the outside, are kept being
identical with each other in length all the time, (iii) the lower
structure group 21 is such that, in a case where the plurality of lower
structures 23 of lower structure group 21 are arranged to be connected to
each other in series, each of the plurality of lower structures 23 can be
rotated around a pin 30, serving as a rotational axis, forward in the
direction of gravitational force but cannot be rotated backward, and (iv)
the upper structure group 22 is such that, in a case where the plurality
of upper structures 22 of the upper structure group 20 are arranged to be
connected to each other in series, each of the plurality of upper
structures 22 can be rotated around a pin 31, serving as a rotational
axis, forward and backward.

[0130] In order to realize such a condition that (i) the one of ends of
the upper structure group 20 and the one of ends of the lower structure
group 21 are connected to the common block member 60, and, in this state,
(ii) the part of the upper structure group 20, protruding from the
opening section 10c' of the third supporting section 10c to the outside,
and the part of the lower structure group 21, protruding from the opening
section 10c' to the outside, are kept being identical with each other in
length, it is necessary to cause the operation of the upper structure
group 20, driven by the drive means 40b for the upper structure group,
and the operation of the lower structure group, driven by the drive means
40a for the lower structure group, to be in synchronization with each
other.

[0131] Further, it is possible that (i) the operation of the upper
structure group 20 is controlled by the drive means 40b for driving the
upper structure group 20, and (ii) the operation of the lower structure
group 21 is controlled by an engaged structure of the bottom surface
convex-concave structure 22a of each of the plurality of upper structures
22 and the upper surface convex-concave structure 23c of the each of the
plurality of lower structures 23.

[0132] Furthermore, it is possible that (i) the operation of the lower
structure group 21 is controlled by the drive means 40a for driving the
lower structure group 21, and (ii) the operation of the upper structure
group 22 is controlled by an engaged structure of the bottom surface
convex-concave structure 22a of each of the plurality of upper structures
22 and the upper surface convex-concave structure 23c of each of the
plurality of lower structures 23.

[0133] Moreover, it is also possible that (i) the operation of the upper
structure group 20 is controlled by the drive means 40b for driving the
upper structure group 20, and (ii) the operation of the lower structure
group 21 is not controlled by the drive means 40a for driving the lower
structure group 21 but the engaged structure of the bottom surface
convex-concave structure 23a of each of the plurality of upper structures
22 and the upper surface convex-concave structure 23c of each of the
plurality of lower structures 23.

[0134] Further, it is possible that (i) the operation of the upper
structure group 20 is not controlled by the drive means 40b for driving
the upper structure group 20, and (ii) the operation of the lower
structure group 21 is controlled by the drive means 40a for driving the
lower structure group 21, and (iii) the operation of the lower structure
group 21 is controlled by the engaged structure of the bottom surface
convex-concave structure 22a of each of the plurality of upper structures
22 and the upper surface convex-concave structure 23c of each of the
plurality of lower structures 23.

[0135] Furthermore, it is also possible that, in order to have an increase
in rigidity of the arm section 2, (i) the operation of the upper
structure group 20, driven by the drive means 40b for the upper structure
group, and the operation of the lower structure group 22, driven by the
drive means 40a for the lower structure group, are caused to be in
synchronization with each other, and (ii) the operation of the upper
structure group 22 is controlled by the engaged structure of the bottom
surface convex-concave structure 22a of each of the plurality of upper
structures 22 and the upper surface convex-concave structure 23c of each
of the plurality of lower structures 23.

[0136] (Modified Example of Arm Section)

[0137] In the present embodiment, the direct acting extensible and
retractable arm joint J3 is constituted by the upper structure group 20
and the lower structure group 21 (see FIG. 2). Note, however, that the
present invention is not limited to this. The present invention can have
either an arrangement illustrated in FIG. 11 or an arrangement
illustrated in FIG. 13. The following description deals with the
arrangement illustrated in FIG. 11 and the arrangement illustrated in
FIG. 13.

[0138] The arrangement illustrated in FIG. 11 is different from the
arrangement illustrated in FIG. 2 in that the upper structure group 21 of
the direct acting extensible and retractable arm joint J3 illustrated in
FIG. 2 is replaced with a different structure. Specifically, a lower
structure 28 (see FIG. 12) is substantially similar to the lower
structure 23 illustrated in FIG. 2 but the upper structure 22 illustrated
in FIG. 2, having substantially a plate structure, is replaced with an
upper structure 27 (see FIG. 12) having a block structure.

[0139] The arrangement illustrated in FIG. 11 is such that (i) the lower
structure group constituted by a plurality of lower structures 28 is such
that, in a case where the plurality of lower structures 28 of the lower
structure group are arranged to be connected to each other in series,
each of the plurality of lower structures 28 can be rotated around a pin,
serving as a rotational axis, forward in the direction of gravitational
force but cannot be rotated backward, and (ii) the upper structure group
constituted by a plurality of upper structures 27 is such that, in a case
where the plurality of upper structures 27 of the upper structure group
are arranged to be connected to each other in series, each of the
plurality of upper structures 27 can be rotated around a pin, serving as
a rotational axis, either forward and backward in the direction of
gravitational force or not backward but only forward in the direction of
gravitational force.

[0140] FIG. 13 illustrates an arrangement in which the arrangement of the
plurality of upper structures 22 and the arrangement of the plurality of
lower structures 23, illustrated in FIG. 2, are reversed in an
up-and-down direction. Each of the plurality of upper structures 22
illustrated in FIG. 2 has substantially a plate structure, whereas each
of a plurality of upper structures illustrated in FIG. 13 has a block
structure which is similar to that of the upper structure 27 illustrated
in FIG. 12. Each of the plurality of lower structures 23 illustrated in
FIG. 2 has a block structure, whereas each of a plurality of lower
structures illustrated in FIG. 13 has a substantially a plate structure.
The arrangement illustrated in FIG. 13 is such that (i) a lower structure
group constituted by the plurality of lower structures is such that, in a
case where the plurality of lower structures of the lower structure group
are arranged to be connected to each other in series, each of the
plurality of lower structures can be rotated around a pin, serving as a
rotational axis, forward in the direction of gravitational force, but
cannot be rotated backward, and (ii) an upper structure group constituted
by the plurality of upper structures is such that, in a case where the
plurality of upper structures of the upper structure group are arranged
to be connected to each other in series, each of the plurality of upper
structures can be rotated around a pin either (i) forward and backward in
the direction of gravitational force or (ii) not backward but only
forward in the direction of gravitational force.

[0141] As illustrated in FIGS. 11 and 13, the upper structure group and
the lower structure group, arranged in parallel with each other in the
horizontal direction, (i) can be coupled with each other by use of the
same mechanism as that of the drive means 40 described above so as to
have a rigid structure, (ii) can release such a coupling structure, and
therefore (iii) can have the same effects as those of the arrangement
illustrated in FIG. 2. Note that, either in the arrangement illustrated
in FIG. 11 or in the arrangement illustrated in FIG. 13, (i) the drive
means 40 illustrated in FIG. 2 can be provided either below the lower
structure group or above the upper structure group, or, alternatively,
(ii) the drive means 40 can be provided blow the lower structure group,
and at the same time, another drive means 40 can be provided above the
upper structure group.

[0142] In other words, as illustrated in FIGS. 11, 12, and 13, the direct
acting extensible and retractable arm joint J3 of the present invention
is formed in such a manner that the upper structure group and the lower
structure group overlap each other to have a rigid structure.

[0143] Further, the inside of the direct acting extensible and retractable
arm joint J3 is a hollowed structure, and a wiring line can be provided
inside the direct acting extensible and retractable arm joint J3. Note,
however, that the present invention is not limited to this. It is
possible that the direct acting extensible and retractable arm joint J3
does not have such a hollowed structure, and the wiring line cannot be
provided inside the direct acting extensible and retractable arm joint
J3. That is, direct acting extensible and retractable arm joint J3 can
have an arrangement in which the upper structure group and/or the lower
structure group have an arrangement in which a plurality of structures,
each having neither a concave shape nor a hollowed shape, are connected
to each other in series.

[0144] The arrangement of the present invention is thus described. Note,
however, that the present embodiment is merely an example of the present
invention. The present invention is not limited to the scope of the
description of the present embodiment, and various alterations and/or
substitutions can be carried out by a skilled person within the scope of
claims.

[0145] (Effects of the Present Embodiment)

[0146] By using the robot arm 50 of the present embodiment, having the
arrangement described above, it is possible to carry out extension and
retraction of the arm of the arm section, without using a bending joint
link. For this reason, it is possible to prevent an object from being
sandwiched between arms due to rotation of a rotational joint provided
between the arms. This effect is a significant advantage for a welfare
robot arm for supporting an operation in a daily life in place of human
power. Further, particularly, according to the robot arm of the present
embodiment, the extension and retraction of the arm is realized by use of
only the direct acting extensible and retractable arm. Accordingly, in a
case where the robot arm of the present embodiment is provided at a wheel
chair or in the vicinity of a bed, as a welfare robot arm, it is possible
to minimize a range in which a user's visibility is limited, as compared
with the arrangement employing the bending joint link between the arms.
Furthermore, an extension/retraction move of the robot arm of the present
embodiment is simple and minimum in front of the user. It is therefore
possible to reduce visual discomfort of the user, as compared with the
arrangement employing the bending joint link between the arms.

[0147] The inventors of the present invention have focused on such a
situation that, generally, in a case where a handicapped person uses a
robot arm as an assistant robot or a welfare robot, saliva of the user or
food particles are likely to adhere to the robot arm. In such a
situation, since the arrangement employing the bending joint link has, on
a surface, a lot of gaps between links, it is likely that a finger is
accidentally withdrawn to the inside of the direct acting extensible and
retractable arm mechanism or an object (a foreign matter or dust)
adhering to the arm section enters the inside of the direct acting
extensible and retractable arm mechanism. This might cause constituents
of the direct acting extensible and retractable arm mechanism not to work
smoothly in combination with each other, and, as a result, it might
become impossible to cause the direct acting extensible and retractable
arm mechanism to be in operation normally. On the other hand, according
to the arrangement of the present invention, the upper surface of the arm
section is a plane surface having no gap. Accordingly, there is no risk
that a normal operation of the direct acting extensible and retractable
arm mechanism is prevented. It is thus possible to realize a robot arm
which has a high reliability in its operation.

Modified Example 1 of the Present Embodiment

[0148] As a matter of course, the extensible and retractable arm mechanism
can be altered variously. For example, shapes of the upper structure 22
and the lower structure 23, or a method of causing the arm section 2 to
have a rigid structure can be changed.

[0149] For example, a length of the upper structure 22 in the longitudinal
direction can be shorter than a length of the lower structure 23 in the
longitudinal direction, as illustrated in FIG. 14.

[0150] Alternatively, the length of the upper structure 22 in the
longitudinal direction can be longer than the length of the lower
structure 23 in the longitudinal direction, as illustrated in FIG. 15.

[0151] The lower structure group 21 is such that adjacent ones of the
plurality of lower structures are coupled with each other via only a pin
30. For this reason, it is possible that, in a case where (i) adjacent
ones of the plurality of lower structures 23 are arranged to be connected
to each other in series such that their concave opening sections face in
the same direction, the adjacent ones of the plurality of lower
structures 23 can be rotated so that their opening sections face outward
to form a V shape. However, as illustrated in FIG. 16, it is possible to
have such an arrangement that (i) each of the plurality of lower
structures 23 includes lock mechanisms 23e and 23f, (ii) when the arm
section is outputted from the opening section 10c' illustrated in FIG. 7,
a lock mechanism 23e of one of adjacent ones of the plurality of lower
structures 23 and a lock mechanism 23f of the other one of adjacent ones
of the plurality of lower structures 23 are connected to each other so
that the adjacent ones of the plurality of lower structures 23 are fixed
and cannot be rotated, and (iii) when the arm section is stored in the
robot arm supporting member 1 via the opening section 10c', the lock
mechanism 23e and the lock mechanism 23f are released from each other so
that the adjacent ones of the plurality of lower structures 23 are
separated from each other and each of the adjacent ones of the plurality
of lower structures 23 can be rotated around a corresponding pin 30
serving as a rotational axis.

Modified Example 2 of the Present Embodiment)

[0152] According to the present embodiment, as illustrated in FIG. 7, (i)
the drive means 40a for the lower structure group includes the drive
mechanism 33 that is constituted by (a) the gear 34 which engages with
the bottom surface convex-concave structure 23a of each of the plurality
of lower structures 23, and (b) the actuator 35 for driving the gear 34,
and the drive means 40a is provided below each of the plurality of lower
structures 23, (ii) the drive means 40b for the upper structure group
includes the drive mechanism that is constituted by (a) the gear which
engages with the upper convex-concave structure of each of the plurality
of upper structures 22 and (b) the actuator for driving the gear, and the
drive means 40b is provided above each of the plurality of upper
structures 22, and (iii) the driving is carried out by use of at least
one of the drive means 40a and the drive means 40b. Note, however, that
the present invention is not limited to this, and the drive means can be
provided either (1) on a left side of the upper structure group and/or
the lower structure group, or (2) on a right side of the upper structure
group and/or the lower structure group.

Modified Example 2-(a)

[0153] First, the following description deals with Modified Example 2-(a).
(a) of FIG. 17 is a perspective view illustrating the upper surface of
the third supporting section 10c (the upper structures 22). (a) of FIG.
17 illustrates a region in the vicinity of the opening section 10c' of
the third supporting section 10c. Here, the plurality of upper structures
22 are connected to each other in series to have a rigid structure in
such a manner that the plurality of upper structures 22 are connected to
the respective plurality of lower structures 23 of the lower structure
group (a deep side in (a) of FIG. 17). According to Modified Example
2-(a), at least the gear 34 is provided on the right side with respect to
an extensible and retractable direction of the arm constituted by the
plurality of upper structures 22 and the plurality of lower structures
23. As illustrated in (b) of FIG. 17, the gear 34 is formed so as to be
in contact with both the plurality of upper structures 22 and the
plurality of lower structures 23. It is possible that in not only the
gear 34 but also the drive mechanism including the actuator for driving
the gear 34 is also provided on the right side of the arm section
constituted by the plurality of upper structures 22 and the plurality of
lower structures 23.

[0154] According to Modified Example 2-(a), it is preferable that a
concave-convex structure which engages with the gear 34 is formed both
(i) on a right surface of each of the plurality of upper structures 22
and (ii) on a right surface of each of the plurality of lower structures
23.

[0155] Further, in the same manner as the arrangement illustrated in FIG.
7, the pressing rollers 41 are provided, respectively, on the right side
of the plurality of upper structures 22 and the plurality of lower
structures 23 and on the left side of the plurality of upper structures
22 and the plurality of lower structures 23. The pressing rollers 41,
provided, respectively, on the right side and on the left side, can be in
contact with both the plurality of upper structures 22 and the plurality
of lower structures 23. Alternatively, the pressing rollers 41 can be in
contact with one of (i) the plurality of upper structures 22 and (ii) the
plurality of lower structures 23.

Modified Example 2-(b)

[0156] Modified Example 2-(b) is such that the drive mechanism of Modified
Example 2-(a) described above, constituted by the gear 34 and the
actuator for driving the gear 34, is provided on the left side of the
plurality of upper structures 22 and the plurality of lower structures
23.

Modified Example 2-(c)

[0157] According to Modified Example 2-(a) described above, the gear 34 is
provided on the right side of the plurality of upper structures 22 the
plurality of lower structures 23, so as to cause both the plurality of
upper structures 22 and the plurality of lower structures 23 to be moved.
Meanwhile, Modified Example 2-(c) is such that the gear 34, which is in
contact with (engages with) the plurality of upper structures 22, is
provided on the right side of the plurality of upper structures 22, and
another gear 34, which is in contact with (engages with) the plurality of
lower structures 23, is provided on the left side of the plurality of
lower structures 23.

[0158] According to the arrangement, it is also possible to realize
successful driving, in the same manner as the embodiment described above.

Modified Example 2-(d)

[0159] Modified Example 2-(d) is such that the positions of the gear 34
and the another gear 34, described in Modified Example 2-(c), are
replaced with each other, that is, the gear 34, which is in contact with
(engages with) the plurality of upper structures 22, is provided on the
left side of the plurality of upper structures 22, and the another gear
34, which is in contact with (engages with) the plurality of lower
structures 23, is provided on the right side of the plurality of lower
structures 23.

Modified Example 2-(e)

[0160] Modified Example 2-(e) is such that (i) the gear provided on the
right side of the plurality of upper structures 22 is in contact with
(engages with) the plurality of upper structures 22, so as to drive both
the plurality of upper structures 22 and the plurality of lower
structures 23, or (ii) the gear provided on the right side of the
plurality of lower structures 23 is in contact with (engages with) the
plurality of lower structures 23, so as to drive both the plurality of
lower structures and the plurality of upper structures 22.

[0161] Alternatively, Modified Example 2-(e) is such that (i) the gear
provided on the left side of the plurality of upper structures 22 is in
contact with (engages with) the plurality of upper structures 22, so as
to drive both the plurality of upper structures 22 and the plurality of
lower structures 23, or (ii) the gear provided on the right side of the
plurality of lower structures 23 is in contact with (engages with) the
plurality of lower structures 23, so as to drive both the plurality of
lower structures 23 and the plurality of upper structures 22.

Modified Example 2-(f)

[0162] Modified Example 2-(f) is such that, in addition to the upper gear
34 and the lower gear 34 of Modified Example 2-(a), provided on the right
side, another upper gear 34 and another lower gear 34 are further
provided on the left side.

[0163] According to Modified Examples 2-(a) through 2-(f), the gear 34 and
the drive mechanism are provided at least one of (i) on the left side of
the arm section and (ii) on the right side of the arm section. With the
arrangement, it is possible to avoid an influence of gravitational force,
as compared with the arrangement in which the gear 34 and the drive
mechanism are provided at an upper position and a lower position,
respectively. Specifically, in a case where the gear 34 and the drive
mechanism are provided at the upper position and lower position,
respectively, as illustrated in FIG. 7, there is an influence, such as
force and torque, on the drive means due to gravitational force
(gravitational force related to the arm section). This might cause an
increase in driving torque and an increase in abrasion. However, with
each of the arrangements of Modified Examples 2-(a) through 2-(f), it is
possible to avoid these problems.

[0164] Further, according to Modified Example 2-(f), it is possible to
carry out driving while maintaining a balance of the arm section with
horizontally-symmetric force by avoiding a situation that (i) driving
force is generated from only one side, (ii) and the other side is
supported by a roller, and, as a result, (iii) horizontally-symmetric
force is cannot be obtained.

Modified Example 3 of the Present Embodiment

[0165] With the drive means illustrated in FIG. 7 or 17, there is a risk
that a tooth plane might be added to a surface of the direct acting
mechanism, and entry of a foreign matter might not be prevented
completely. Further, there is also a risk that the tooth plane might be
in contact with a human or an object in the vicinity of the direct acting
mechanism. In view of these, it is possible to have such an arrangement
that the tooth plane is deleted from the surface of the direct acting
mechanism, so as to avoid the entry of a foreign matter. Further, in
order to eliminate the risk that the tooth plane is in contact with a
human or an object in the vicinity of the direct acting mechanism, it is
possible to provide the gear 34 between the upper structure group 20 and
the lower structure group 21, as illustrated in FIG. 18. That is, the
tooth plane is added to a bottom section of each of the plurality of
upper structures 22 (a surface which faces the plurality of lower
structures 23), and the tooth plane is driven by the drive means. With
the arrangement, it is possible to cause both the upper structure group
and the lower structure group to be in operation. The tooth plane of the
bottom section of each of the plurality of upper structures 22 can also
be used to engage with a corresponding one of the plurality of lower
structures. 23.

[0166] It is necessary that, before the upper structure group 20 is in
contact with the gear 34, the upper structure group 20 is arranged
linearly (maintained horizontally) by use of a roller. For this reason, a
first roller is provided in the upstream with respect to the gear, a
second roller is provided in the downstream with respect to the gear, and
a third roller is provided above the gear. The drive means is located on
a backside with respect to the opening section 10c' of the third
supporting section 10c. Accordingly, it becomes possible to cause the
opening section 10c' to have a small size. Further, since gravitational
force does not have an influence on the drive means, it is possible to
have a reduction in driving torque and a reduction in abrasion.

[0167] The present invention is not limited to the description of the
embodiments above, but may be altered by a skilled person within the
scope of the claims. An embodiment based on a proper combination of
technical means disclosed in different embodiments is encompassed in the
technical scope of the present invention. The embodiments and concrete
examples of implementation discussed in the foregoing detailed
explanation serve solely to illustrate the technical details of the
present invention, which should not be narrowly interpreted within the
limits of such embodiments and concrete examples, but rather may be
applied in many variations within the spirit of the present invention,
provided such variations do not exceed the scope of the patent claims set
forth below.

CONCLUSION OF THE PRESENT INVENTION

[0168] As described above, a direct acting extensible and retractable arm
mechanism of the present invention includes: a robot arm supporting
member; a robot arm supporting member; and an arm section being
extensible and retractable directly from one of ends of the robot arm
supporting member, the arm section being such that a hand section is
attachable to one of ends of the arm section, the arm section being
constituted by (i) a first structure group in which a plurality of first
structures are coupled with each other in series in such a manner that
adjacent ones of the plurality of first structures are coupled with each
other via a corresponding one of a plurality of first coupling axes in a
direction which is orthogonal to a direction of the corresponding one of
the plurality of first coupling axes and (ii) a second structure group in
which a plurality of second structures are coupled with each other in
series in such a manner that adjacent ones of the plurality of second
structures are coupled with each other via a corresponding one of a
plurality of second coupling axes in a direction which is orthogonal to a
direction of the corresponding one of the plurality of second coupling
axes, the plurality of first structures being identical with each other
in width in a direction parallel to the plurality of first coupling axes,
the plurality of second structures being identical with each other in
width in a direction parallel to the plurality of second coupling axes,
the first structure group and the second structure group being coupled
with each other in such a manner that one of two end first structures of
the plurality of first structures, on a hand section side, and one of two
end second structures of the plurality of second structures, on the hand
section side, are coupled with each other, the robot arm supporting
member including, at one of ends of the robot arm supporting member,
drive means for (i) pressing the first structure group and the second
structure group so that the first structure group and the second
structure group become closer to each other and become in contact with
each other, (ii) causing the first structure group and the second
structure group to overlap each other so that a surface of the first
structure group and a surface of the second structure group, which
surfaces are in contact with each other, do not slip with respect to each
other, and (iii) driving the first structure group and the second
structure group in a direction in which the arm section is extensible, in
a case where the drive means causes the first structure group and the
second structure group to overlap each other, the first structure group
and the second structure group forming such a rigid arm section that
rotation of each of the plurality of first structures via the
corresponding one of the plurality of first coupling axes and rotation of
each of the plurality of second structures via the corresponding one of
the plurality of second coupling axes are prevented, at least one of the
first structure group and the second structure group is such that
adjacent ones of structures engage with each other via their side
surfaces, and form a plane surface having no gap, which plane surface
faces and is in contact with a surface of the other one of the first
structure group and the second structure group, the robot arm supporting
member including separation means in the robot arm supporting member, in
a case where the drive means carries out reverse driving, the separation
means causes the first structure group and the second structure group to
be separated from each other so that (i) each of the plurality of first
structures is rotatable around the corresponding one of the plurality of
first coupling axes and (ii) each of the plurality of second structures
is rotatable around the corresponding one of the plurality of second
coupling axes.

[0169] Further, in addition to the arrangement, the direct acting
extensible and retractable arm mechanism of the present invention is
preferably arranged such that in a case where (i) the drive means causes
the first structure group and the second structure group to overlap each
other and therefore (ii) the arm section becomes rigid in such a manner
that the rotation of each of the plurality of first structures via the
corresponding one of the plurality of first coupling axes and the
rotation of each of the plurality of second structures via the
corresponding one of the plurality of second coupling axes are prevented,
and one of the first structure group and the second structure group is
provided above the other one of the first structure group and the second
structure group, the one of the first structure group and the second
structure group is such that adjacent ones of structures engage with each
other via their side surfaces and forms a plane surface having no gap,
which plane surface is opposite to a surface that is in contact with a
surface of the other one of the first structure group and the second
structure group.

[0170] Furthermore, in addition to the arrangement, the direct acting
extensible and retractable arm mechanism of the present invention is
preferably arranged such that the first structure group is such that
adjacent ones of the plurality of first structures engage with each other
via their side surfaces and form a plane surface having no gap, which
plane surface is opposite to a surface that is in contact with a surface
of the second structure group, and the second structure group is such
that adjacent ones of the plurality of second structures engage with each
other via their side surfaces and form a plane surface having no gap,
which plane surface is opposite to the surface that is in contact with
the surface of the first structure group.

[0171] Moreover, in addition to the arrangement, the direct acting
extensible and retractable arm mechanism of the present invention is
preferably arranged such that the one of two end first structures of the
plurality of first structures and the one of two end second structures of
the plurality of second structures are physically attached to each other
or physically welded with respect to each other.

[0172] Further, in addition to the arrangement, the direct acting
extensible and retractable arm mechanism of the present invention is
preferably arranged such that the one of two end first structures of the
plurality of first structures and the one of two end second structures of
the plurality of second structures are combined with a common block.

[0173] Furthermore, in addition to the arrangement, the direct acting
extensible and retractable arm mechanism of the present invention
preferably further includes: a pressing member for supporting said
pressing of the first structure group and the second structure group, the
pressing member pressing at least one of the first structure group and
the second structure group.

[0174] Moreover, in addition to the arrangement, the direct acting
extensible and retractable arm mechanism of the present invention is
preferably arranged such that the drive means is such that (i) the drive
means includes a drive mechanism constituted by a gear(s) and an actuator
for rotating the gear(s), and the gear(s) is in contact with one of the
first structure group and the second structure group so as to drive both
the first structure group and the second structure group, or (ii) the
drive means includes two drive mechanisms each being constituted by a
gear(s) and an actuator for rotating the gear(s), and the gear(s) of one
of the two drive mechanisms is in contact with one of the first structure
group and the second structure group and the gear(s) of the other one of
the two drive mechanisms is in contact with the other one of the first
structure group and the second structure group, so as to drive both the
first structure group and the second structure group.

[0175] Further, in addition to the arrangement, the direct acting
extensible and retractable arm mechanism of the present invention is
preferably arranged such that the gear is provided between the first
structure group and the second structure group.

[0176] Furthermore, in addition to the arrangement, the direct acting
extensible and retractable arm mechanism of the present invention is
preferably arranged such that a length from a surface of each of the
plurality of first structures constituting the first structure group,
which surface is in contact with the second structure group, to an
opposite surface of each of the plurality of first structure, and a
length from a surface of each of the plurality of second structures
constituting the second structure group, which surface is in contact with
the first structure group, to an opposite surface of each of the
plurality of second structures, are identical with each other or
different from each other.

[0177] Moreover, in addition to the arrangement, the direct acting
extensible and retractable arm mechanism of the present invention is
preferably arranged such that, in a case where (i) the drive means causes
the first structure group and the second structure group to overlap each
other and therefore (ii) the arm section becomes rigid in such a manner
that the rotation of each of the plurality of first structures via the
corresponding one of the plurality of first coupling axes and the
rotation of each of the plurality of second structures via the
corresponding one of the plurality of second coupling axes are prevented,
one of the first structure group and the second structure group is
provided above the other one of the first structure group and the second
structure group, and a plurality of coupling axes of the other one of the
first structure group and the second structure group are located below a
plurality of coupling axes of the one of the first structure group and
the second structure group in a direction of gravitational force.

[0178] Further, in addition to the arrangement, the direct acting
extensible and retractable arm mechanism of the present invention is
preferably arranged such that, in a case where (i) the drive means causes
the first structure group and the second structure group to overlap each
other and therefore (ii) the arm section becomes rigid in such a manner
that the rotation of each of the plurality of first structures via the
corresponding one of the plurality of first coupling axes and the
rotation of each of the plurality of second structures via the
corresponding one of the plurality of second coupling axes are prevented,
one of the first structure group and the second structure group is
provided above the other one of the first structure group and the second
structure group, and each of a plurality of coupling axes of the other
one of the first structure group and the second structure group is
located below a region between adjacent ones of a plurality of coupling
axes of the one of the first structure group and the second structure
group in a direction of gravitational force.

[0179] Furthermore, in addition to the arrangement, the direct acting
extensible and retractable arm mechanism of the present invention is
preferably arranged such that a surface of the first structure group and
a surface of the second structure group, which surfaces are in contact
with each other, have, respectively, gear sections which engage with each
other.

[0180] Moreover, in addition to the arrangement, the direct acting
extensible and retractable arm mechanism of the present invention is
preferably arranged such that each of a plurality of structures
constituting one of the first structure group and the second structure
group has a plurality of gear sections on its surface which is in contact
with a surface of the other one of the first structure group and the
second structure group, and the plurality of gear sections engage with
both gear sections of adjacent ones of a plurality of structures of the
other one of the first structure group and the second structure group.

[0181] Further, in addition to the arrangement, the direct acting
extensible and retractable arm mechanism of the present invention is
preferably arranged such that the robot arm supporting member is capable
of storing, inside the robot arm supporting member, the first structure
group and the second structure group which have been separated from each
other by the separation means, and the first structure group and the
second structure group, separated from each other by the separation
means, are stored along an inner shape of the robot arm supporting member
by (i) the rotation of each of the plurality of first structures via the
corresponding one of the plurality of first coupling axes and (ii) the
rotation of each of the plurality of second structures via the
corresponding one of the plurality of second coupling axes.

INDUSTRIAL APPLICABILITY

[0182] A robot arm of the present invention includes an arm section
constituted by a direct acting extensible and retractable arm mechanism
including a plurality of upper structures, a plurality of lower
structures, and drive means. Accordingly, with the robot arm, it is
possible to (i) prevent significantly a finger from being sandwiched in
the robot arm or prevent significantly dust from entering the robot arm,
and (ii), by storing the direct acting extensible and retractable arm
mechanism in a robot arm supporting member, realize a reduction in a
space necessary for the robot arm.

[0183] Accordingly, for example, the robot arm of the present invention
can be used by a handicapped person as a support robot or a welfare
robot, and is also used as a robot arm for producing a next-generation
robot arm for cellular manufacturing, which operates in the vicinity of a
human in cooperation with the human.